The immigration and customs official says Radojkovic was accompanied by U.S. immigration agents who turned him over to Bosnia-Herzegovina law enforcement officials.

Investigators say the 61-year-old Radojkovic moved to the United States in 1999 and lived in Las Vegas, where he was arrested in 2009.

Prosecutors in Bosnia-Herzegovina say Radojkovic led a police brigade that rounded up about 200 Bosnian Muslim men for execution after Bosnian Serb forces overran United Nations peacekeepers in Srebrenica.